Laminate panels for constructing enclosure



Sept. 1, 1964 H. G. MATHEWS 3,147,336

LAMINATE PANELS FOR CONSTRUCTING ENCLOSURE Filed April 17, 1962 2 Sheets-Sheet 1 V FIG. 2

I? l4' l2 INVENTOR. HOWARD G. MATHEWS A TTORN Y3.

Sept. 1964 H. G. MATHEWS 3,147,336

, LAMINATE PANELS FOR CONSTRUCTING ENCLOSURE vFiled April 17, 1962 2 Sheets-Sheet 2 FIG. 4

INVENTOR. HOWARD G. MATHEWS A TT NE Y3.

United States Patent 3,147,336 LAMINATE PANELS FOR CONSTRUCTING ENCLOSURE Howard G. Mathews, 2 Pensdale Lane, Levittown, NJ. Filed Apr. 17, 1962, Ser. No. 188,168 6 Claims. (Cl. 174-35) The present invention relates to improved laminate panels for constructing enclosures. In one of its more specific aspects the present invention relates to panels suitable for use in producing radio frequency enclosures for electronic apparatus. For such enclosures it is essential that the magnetic shielding prevent all magnetic rays from entering the enclosure.

In certain known radio frequency enclosures adjacent magnetic shielding panels are secured together by compression joints. However, with known constructions the absolute seal required in magnetic shielding applications cannot be maintained since the bolts of the compression joint eventually become loosened due to movement of instruments and personnel in and out of the enclosure.

The panels of the present invention avoid the above problem by providing resilient sealing strips integral with the core of the panel and interiorly of exterior metallic cover members of the panel. The resilient strips which are formed preferably of rubber and compress under pressure as the compression joint is tightened. The resiliency of the sealing strips in tending to expand against the action of the compression joint member maintains an absolute seal even though the bolts of the joint member may loosen somewhat during use of the enclosure.

Since it is often essential to maintain a close control of the temperature within the enclosure so that the calibration of the instruments is not affected, the cores of the panels of the present invention are made of material having low thermal conductivity such as a rigid polyurethane foam.

Panels designed to form a portion of the ceiling of the enclosure may be provided with reinforcing means so that support elements may be hung therefrom.

One of the primary objects of the present invention is to provide improved laminate panels for fabricating enclosures.

Another object of the present invention is to provide improved radio frequency shielding panels having low thermal conductivity.

Still another object of the present invention is to provide improved radio frequency shielding panels having integral compressible sealing strips along the edges thereof.

A further object of the present invention is to provide an improved radio frequency shielding enclosure having improved compression joint means between adjacent panels that maintain an absolute seal regardless of slight loosening of bolt members in the joint means.

A still further object of the present invention is to pro vide laminate panels with reinforcing means adapting the panels to be used as load-supporting members in the ceiling of an enclosure.

These and other objects, features and advantages of the present invention will become more apparent from the following description and the accompanying drawings wherein:

FIGURE 1 is a partial perspective view of a laminate panel in accordance with the present invention with parts 3,147,336 Patented Sept. 1, 1964 thereof broken away to better illustrate the structure of the panel,

FIGURE 2 is an exploded vertical sectional view of the panel shown in FIGURE 1,

FIGURE 3 is a partial sectional view showing compression joint means uniting adjacent laminate panels, which panels constitute another embodiment of the presentinvention,

FIGURE 4 is a partial perspective view substantially similar to that of FIGURE 1 of one of the panels shown in FIGURE 3, and

FIGURE 5 is a partial perspective exploded view of a panel having longitudinal reinforcing means with one cover member removed.

Referring now to the drawings and more particularly to FIGURES 1 and 2, reference numeral 10 designates a laminate panel having a core 11 of low thermal conductivity, cover members 12 and 13, and a resilient sealing member 14 around the perimeter of the panel. The core 11 of low thermal conductivity is preferably a rigid polyurethane foam having a thermal conductivity in the range of 0.13 and a density consistent with the usage of the panel. When the panels are utilized for fabricating radio frequency shielding enclosures, cover members 12 and 13 are made of a suitable shielding material, such as 24 gauge zinc-covered steel. Galvanized steel, aluminum, copper, stainless steel and other suitable metals may also be employed.

Resilient sealing member 14 preferably consists of assembled extruded strips of GR-S. synthetic rubber or natural rubber capable of withstanding forces in the order of 600 p.s.i. It has been found that rubber having a hardness of -80 durometers is especially well suited for the intended use. While such rubber is preferred, other materials having similar characteristics may also be utilized, for example, high density flexible polyurethane foam.

Flexible strips of the requisite size to constitute the rectangular configuration of resilient sealing member 14 evident from FIGURE 1 may be secured by means of an adhesive to one of the cover members 12, 13 along the outer perimeter thereof and placed in a mold such as that shown in my copending application Serial No. 144,877, filed October 13, 1961, entitled Plastic Foams, whose subject matter is incorporated herein insofar as necessary. The chemicals required for producing rigid core 11 are introduced into the mold, the other cover member inserted, the mold closed, and core 11 foamed therein to manufacture panel 10.

A modified panel construction is shown in FIGURES 3 and 4. Whereas in the embodiment of FIGURES 1 and 2, sealing member 14 is extended the full distance between cover members 12 and 13; in the panel shown in FIGURES 3 and 4, two smaller resilient sealing elements 14 are provided which are separated from each other by a projecting rim portion 11 of core 11.

Referring to FIGURE 3, the adjacent panels are secured together by compression joint means including a plate member 15 overlying edge portions of adjacent cover members 13, a bolt 16, and compression surfaces 17 abutting adjacent covers 12 and interconnected by U-shaped portion 18 provided with a recess having threads complementary to the threads of bolt 16. As plate member 15 and surfaces 17 are drawn against cover members 12 and 13 by tightening bolt 16, the underlying edges of members 12 and 13 are bent inwardly; and resilient inserts 14 are compressed. The compressing of inserts 14' which tend to expand back to their original size stores a force which is effective to maintain a tight seal between panel cover members 12 and 13 and the joint structure in the event that bolt 16 should be inadvertently loosened during movement of instruments and/ or personnel in and out of the enclosure.

It will be appreciated that the resilient sealing member 14 of FIGURES 1 and 2 functions in an analogous manner to maintain a tight joint between adjacent panels. It will be further appreciated that in lieu of the butt joint shown in FIGURE 3, corner joints of known general configuration will be provided for securing adjacent horizontal and vertical panels together.

FIGURE 5 illustrates a ceiling panel reinforced by reinforcing elements 19 bonded together by a suitable se curing means as an adhesive. It has been found that long leaf yellow pine boards have strength characteristics suitable for use as reinforcing elements 19. Elements 19 with adhesive between adjacent boards may be placed in the mold so that the adhesive is set at the same time that the reinforcing elements are bonded to the rigid core 11. For the sake of clarity, cover member 12 has been omitted in FIGURE 5 so as to better show the interior details of the panel construction. Resilient sealing member 14" of FIGURE 5 functions similarly to the previously dis cussed sealing members 14 and 14 of the other embodiments. While in FIGURE 5 sealing element 14" is shown only at the upper outer edge of the panel, such sealing means might also be provided adjacent lower cover member 13.

Vertically extending holes of which only one is shown in FIGURE 5 extend through lower cover member 13 and reinforcing elements 19 to receive an eyelet member 21. Each hole 20 terminates in a hexagonal recess 22 housing a nut 23 and a washer 24. Nut 23 receives the threaded upper end 25 of eyelet member 21. It will be appreciated that the illustrated support members are merely illustrative of support means which may be secured to reinforcing elements 19.

Brackets 26 having apertures 27 for receiving screw members (not shown) may be provided to strengthen the joint between the ceiling and wall panels. The wall panels may also be provided with vertically extending reinforcing posts 28 to receive the screw members of bracket 26.

While the present invention has been described particularly with reference to a radio frequency shielding enclosure and similar test enclosures, it will be appreciated that the invention is not so limited. For example, the rein forced panel shown in FIGURE 5 may be used as an overhead support for meat rails in transportation equipment hauling carcass meats since the panel has low thermal conductivity and also combines high strength with low weight.

Accordingly, it is apparent that the present invention is susceptible to many changes and modifications within the spirit and scope of the present invention, and I intend to cover all such changes and modifications as are encompassed by the scope of the appended claims.

I claim:

1. A radio frequency shielding enclosure comprising a plurality of laminate panels, and compression joint means uniting adjacent panels, each panel including a light, rigid core, resilient edge strip means secured along edge portions of said core, and inner and outer metallic cover members in combination with said edge strip means enclosing said core, said cover members being secured to opposite side faces of said edge strip means, said compression joint means including compression members overlying the edges of the cover members of adjacent panels on both sides of the panels, said edge strip means being compressed by said compression joint means and being effective to maintain a good seal between said compression joint means and the adjacent panels in spite of inadvertent minor loosening of said compression joint means.

2. An enclosure comprising a plurality of laminate panels, and compression joint means uniting adjacent panels, each panel including a light, rigid core, resilient edge strip means secured along edge portions of said core, and inner and outer metallic cover members in combination with said edge strip means enclosing said core, said cover members being secured to opposite side faces of said edge strip means, at least one of said panels also including a plurality of abutting longitudinally extending reinforcing members and means for supporting elements within the enclosure secured to said reinforcing elements and extending through an aperture provided in said inner cover member, said edge strip means being compressed by said compression joint means in a direction transverse to the plane of said panels and being effective to maintain a good seal between said compression joint means and the adjacent panels in spite of inadvertent minor loosening of said compression joint means.

3. A radio frequency shielding enclosure comprising a plurality of laminate panels, and compression joint means uniting adjacent panels, each panel including a light, rigid core, resilient edge strip means secured along edge portions of said core, and inner and outer metallic cover members having sufficient conductivity to affect shielding of radio frequency waves, said cover members being secured to opposite side faces of said edge strip means and in combination with said edge strip means enclosing said core, said compression joint means including compression members overlying the edges of the cover members of adjacent panels on both sides of the panels, said edge strip means being compressed by said compression joint means in a direction transverse to the plane of said panels and being effective to maintain a good seal between said compression joint means and the adjacent panels in spite of inadvertent minor loosening of said compression joint means.

4. An enclosure comprising a plurality of laminate panels, and compression joint means uniting adjacent panels, each panel including a light, rigid core, resilient edge strip means secured along edge portions of said core and inner and outer metallic cover members in combination with said edge strip means enclosing said core, said cover members being secured to opposite side faces of said edge strip means, at least one of said panels also including a plurality of abutting longitudinally extending re- 1nforcing members and means for supporting elements within the enclosure secured to said reinforcing elements and extending through an aperture provided in said inner cover member, said edge strip means being compressed by said compression joint means in a direction transverse to the plane of said panels and being effective to maintain a good seal between said compression joint means and the ad acent panels in spite of inadvertent minor loosening of said compression joint means, said cover members having an electrical conductivity approximately equal to that of copper so as to be efiicient in shielding radio frequency waves.

5. An enclosure comprising a plurality of laminate panels, and compression joint means uniting adjacent panels, each panel including a relatively rigid polyurethane foam core of low thermal conductivity, resilient edge strips of a hardness in the order of 70-80 Durometers secured at edge surfaces of said core and approximately corresponding in size to the thickness of said core, and spaced radio frequency shielding cover members overlying and secured to opposite sides of said core and said edge strips, said core being completely enclosed by said cover members and said edge strips, said compression joint means including compression members overlying the edges of said cover members of adjacent panels on both sides of the panels, said edge strips being compressed by said compression joint means in a direction transverse to the plane of said panels, said cover members having an elec trical conductivity approximately equal to that of copper so as to be efficient in shielding radio frequency waves.

6. An enclosure comprising a plurality of laminate panels, and compression joint means uniting adjacent panels, each panel including a relatively rigid core of low thermal conductivity having a projecting rim portion around the perimeter thereof, edge strips of resilient material abutting on opposite sides of the projecting rim portion of said core, and metallic cover members bonded to opposite sides of said core and said edge strips, said compression joint means including compression members overlying the edges of the cover members of adjacent panels on both sides of said panels, said edge strips being compressed by said compression joint means in a direction transverse to the plane of said panels, said cover members having an electrical conductivity approximately equal to that of copper so as to be efiicient in shielding radio fre quency waves.

References Cited in the file of this patent UNITED STATES PATENTS 2,376,653 Boyer May 2, 1945 2,808,624 Sullivan Oct. 8, 1957 2,838,592 Feketics June 10, 1958 2,860,176 Lindgren Nov. 11, 1958 2,961,478 Burns Nov. 22, 1960 

6. AN ENCLOSURE COMPRISING A PLURALITY OF LAMINATE PANELS, AND COMPRESSION JOINT MEANS UNITING ADJACENT PANELS, EACH PANEL INCLUDING A RELATIVELY RIGID CORE OF LOW THERMAL CONDUCTIVITY HAVING A PROJECTING RIM PORITON AROUND THE PERIMETER THEROF, EDGE STRIPS OF RESILIENT MATERIAL ABUTTING ON OPPOSITE SIDES OF THE PROJECTING RIM PORTION OF SAID CORE, AND METALLIC COVER MEMBERS BONDED TO OPPOSITE SIDES OF SAID CORE AND SAID EDGE STRIPS, SAID COMPRESSION JOINT MEANS INCLUDING COMPRESSION MEMBERS OVERLYING THE EDGES OF THE COVER MEMBERS OF ADJACENT PANELS ON BOTH SIDES OF SAID PANELS, SAID EDGE STRIPS BEING COMPRESSED BY SAID COMPRESSION JOINT MEANS IN A DIRECTION TRANSVERSE TO THE PLANE OF SAID PANELS, SAID COVER MEMBERS HAVING AN ELECTRICAL CONDUCTIVITY APPROXIMATELY EQUAL TO THAT OF COPPER SO AS TO BE EFFICIENT IN SHIELDING RADIO FREQUENCY WAVES. 